Abstract

tTo improve the transport characteristics of a catalytic fixed-bed via optimal design of catalystpellet specifications such as the pellet diameter it is necessary to account for all physico-chemical phenomena influenced by the pellet. For the approximative description of thetransport phenomena on the catalyst pellet scale a new shortcut method is developed inthis work. It enables a generalized and system independent treatment of the aforementionedprocesses and can be applied to arbitrary reaction networks and reaction kinetic models.Based on linearization and decoupling of the pellet balance equations the method yields ananalytical solution. This allows for model-based design of the reactor-catalyst system viadynamic optimization at reduced computational costs as the use of complex heterogeneousmodels is avoided. In order to ensure accurate predictions of the method, regions with highcatalyst utilization are targeted.To indicate the potential of improved bed transport characteristics, the shortcut method isapplied to the reactor-catalyst system for ethylene oxide synthesis. The system is optimizedin terms of reducing the pressure drop while meeting other reactor performance constraints.The pressure drop could be reduced by more than 60%. The shortcut method is validatedusing a rigorous stand-alone model of the catalyst pellet.